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S J Brull

Publications and source records attributed to S J Brull.

72 records · Page 4Linked to original sources
PubMed1991

Effect of tetanus on subsequent neuromuscular monitoring in patients receiving vecuronium.

The current study evaluated the effects of tetanic stimulation on neuromuscular responses to serial train-of-four (TOF) and double-burst stimulation (DBS). For TOF monitoring (n = 13), a degree of neuromuscular blockade was achieved with an intravenous vecuronium infusion such that the ratio of fourth twitch (T4) to first twitch (T1), T4/T1, was stable at a value between 0.1 and 0.7. Four seconds after a 5-s, 50-Hz tetanic stimulus was delivered, TOF monitoring was resumed at 10-s intervals. Significant changes were noted for T1, T4, and T4/T1, with median increases of 38, 250, and 93%, respectively. The median times for T1, T4, and T4/T1 to return to within 10% of their pretetanic (baseline) values were 34, 43, and 34 s, respectively (P = nonsignificant [NS] among times to recovery). A 100-Hz tetanic stimulus induced 50, 300, and 178% median increases of T1, T4, and T4/T1, while corresponding values for recovery times were 53, 73, and 54 s. For DBS monitoring (n = 14), tetanic stimulation (50-Hz, 5-s) induced 38, 300, and 153% median increases of the DBS3,3 parameters (first response [D1], second response [D2], and their ratio [D2 not equal to D1], respectively). The posttetanic effects on D1, D2, and D2/D1 persisted for 43, 66, and 46 s, respectively. For DBS3,2, median posttetanic (50-Hz, 5-s) increases were 41, 275, and 176%, while corresponding times to recovery were 43, 43, and 43 s. Although the data indicate that the posttetanic percent increase was at least 10 times larger at greater degrees of blockade (T4/T1 = 0.1) than at lesser degrees (T4/T1 = 0.7), all T4/T1 and D2/D1 ratios returned to within 10% of baseline in 125 s or less after 5-s tetanic stimulation.

Adult↗
PubMed1991

Visual assessment of train-of-four and double burst-induced fade at submaximal stimulating currents.

The influence of current intensity on visual assessment of fade in response to train-of-four (TOF) and two modes of double-burst stimulation (DBS) was determined to assess the utility of low-current neurostimulation. Each of 150 sets of assessments (in 51 patients) included a mechanographic TOF at 60 mA followed by visual assessments of TOF, DBS3,3 (two minitetanic bursts of three stimuli each), and DBS3,2 (a burst of three followed by a burst of two impulses) at 20, 30, 50, and 60 mA in random order. For the range of mechanographic TOF ratios between 0.41 and 0.70, visual assessment of TOF fade failed to identify fade in 33%, 36%, 44%, and 58% of cases at 20, 30, 50, and 60 mA, respectively. Corresponding false-negative rates for DBS3,3 were 11%, 17%, 36%, and 33%, and for DBS3,2 they were 6%, 6%, 17%, and 28%. Within each method, P less than 0.05 (by Mantel-Haenszel analysis) for a linear trend of increasing accuracy as current decreased. For the range between 0.41 and 0.70, quantitative assessment overestimated the actual ratio at all currents for TOF, at 30, 50, and 60 mA for DBS3,3, and at 50 and 60 mA for DBS3,2 (P less than 0.05 by Wilcoxon signed rank test). At each current tested, DBS was more sensitive in detecting fade visually than TOF. The accuracy of visual fade detection was not influenced significantly by level of observer training. In conclusion, visual assessment of fade by novice and expert observers is improved by testing at low currents.

Adolescent↗
PubMed1990

Stimulation with submaximal current for train-of-four monitoring.

The present study evaluated responses to train-of-four (TOF) stimulation at a range of stimulating currents. Traditionally TOF has been applied with a supramaximal stimulus but this may be quite uncomfortable for the awake patient. In the first part of this study, 12 healthy volunteers quantified (by 10-cm visual analog scale) the discomfort associated with TOF stimulation at 20, 30, and 50 mA. The median VAS scores were 2, 3, and 6, respectively (P less than 0.05 for differences between each group). In the second part, single twitch and TOF responses were compared at 20, 30, and 50 mA in 64 postoperative and in 19 intraoperative patients who had ratios of the fourth to the first twitch (T4/T1) ranging from 0.15-1.03. In all patients, neuromuscular responses to nerve stimulation were recorded by a mechanogram, and the T4/T1 ratios were calculated. Although single twitch heights increased significantly as amperage was increased, there was no statistical difference in the T4/T1 ratios at the three different currents. The mean +/- SD T4/T1 ratios at 20, 30, and 50 mA were 0.795 +/- 0.247, 0.798 +/- 0.237, and 0.802 +/- 0.233, respectively (P = ns). It is concluded that TOF monitoring using a submaximal stimulus is more comfortable for the awake patient who is suspected of residual weakness, and that T4/T1 testing can be reliably accomplished intraoperatively as well as postoperatively using submaximal stimuli.

Anesthesiology↗
PubMed1990

Subjective responses to train-of-four and double burst stimulation in awake patients.

The present study was undertaken to determine whether the discomfort associated with the sequential bursts of stimuli comprising the two recommended forms of double burst stimulation (DBS) is comparable to that associated with the repetitive stimuli of train-of-four (TOF). Twenty-one unmedicated volunteers rated on a visual analog scale the discomfort associated with randomly applied DBS and TOF stimulations at 20, 30 and 50 mA. All participants were blinded to the mode of stimulation, as well as to the current intensity. At each amperage tested, TOF produced significantly less discomfort than either form of DBS (P less than 0.01). Stimulation at 50 mA produced median visual analog scale scores of 7.5, 7.0, and 5.0 for DBS3,2, DBS3,3, and TOF, respectively. At 30 mA the corresponding median visual analog scale scores were 4.5, 5.5, and 3.0, whereas at 20 mA the scores were 4.0, 4.5, and 2.0, respectively. Thus, DBS is more uncomfortable than TOF at each current tested; however, in light of reports of its higher sensitivity, DBS may be the preferred means of assessing neuromuscular function in the awake as well as the anesthetized patient when a force transducer and recorder are not readily available.

Adult↗
PubMed1990

Correlation of train-of-four and double burst stimulation ratios at varying amperages.

The present study was undertaken to document the relationship between train-of-four (TOF) and double burst stimulation (DBS) at varying degrees of blockade, and to determine whether this relationship remained constant over a range of stimulating currents. The neuromuscular responses to the two most commonly employed modes of DBS stimulation, DBS3,3 and DBS3,2, and the responses to TOF nerve stimulation were recorded and compared at 20, 30, and 50 mA. Twenty-two consenting patients undergoing general anesthesia received a vecuronium infusion to achieve a TOF ratio within the range of 0.1-1.0. Train-of-four, DBS3,3, and DBS3,2 were delivered at 20, 30, and 50 mA in random sequence after a steady state of neuromuscular blockade was achieved. At a stimulating current of 50 mA, there was a significant linear correlation between DBS3,3 and TOF (P less than 0.0001; r = 0.98) over the range of blockade. Similarly, there was a high degree of correlation between DBS3,2 and TOF at 50 mA, as the increased "fade" associated with DBS3,2 was maintained throughout the spectrum of blockade (P less than 0.0001; r = 0.95). The high degrees of correlation were maintained at stimulating currents of 20 and 30 mA (P less than 0.0001). In conclusion, the present study revealed that there is a high degree of linear correlation between DBS and TOF, and that this mechanographic relationship is maintained over a wide range of stimulating currents during varying degrees of clinical neuromuscular blockade.

Adult↗
PubMed1989

An evaluation of morphine and oxymorphone administered via patient-controlled analgesia (PCA) or PCA plus basal infusion in postcesarean-delivery patients.

The analgesic efficacy and adverse effects of morphine and oxymorphone in 32 patients who received traditional patient-controlled analgesia (PCA) following cesarean delivery were compared with those in 32 other patients receiving the same agents via PCA plus basal opioid infusion (PCA + BI). All patients were operated upon during epidural anesthesia with 2% lidocaine and 1:200,000 epinephrine to achieve a T4 sensory level. Upon first complaint of pain in the recovery room, patients were given a titrated iv loading dose of the assigned opioid until comfortable and were then provided with a programmable PCA device. Group I (PCA) consisted of two subsets in which incremental boluses of morphine (1.8 mg, n = 16) or oxymorphone (0.3 mg, n = 16) could be self-administered via conventional PCA. Patients in group II (PCA + BI) received a basal infusion of morphine (0.6 mg/hour, n = 16) or oxymorphone (0.1 mg/hour, n = 16) in addition to self-administered boluses of 1.8 and 0.3 mg, respectively. Patients were evaluated for 24 h following initiation of analgesic therapy, and 10-cm visual analog scales (VAS) were utilized at selected intervals to assess pain at rest, pain during movement, and satisfaction with therapy. The level of sedation and incidence of nausea/vomiting and pruritus were also recorded. Patients utilizing PCA + BI noted significant reductions in resting pain scores with oxymorphone and decreased pain during movement with both opioids when compared with individuals using PCA alone (P less than 0.05). There were no significant differences between treatment groups in 24-h dose requirements or patient satisfaction with therapy (P = ns).(ABSTRACT TRUNCATED AT 250 WORDS)

Cesarean Section↗
PubMed1989

Time-courses of zones of differential sensory blockade during spinal anesthesia with hyperbaric tetracaine or bupivacaine.

The purposes of this study were twofold: to compare bupivacaine and tetracaine spinal anesthesia with regard to the zones of differential sensory blockade and to evaluate the time-courses of the widths of the zones of differential sensory blockade during spinal anesthesia. In 51 patients, the most rostral levels of sensory denervation to light touch, pinprick, and temperature discrimination were measured. There was no statistically significant difference in the height of sensory blockade in the 29 patients given bupivacaine and in the 22 patients given equipotent doses of tetracaine. The widths of the zones of differential blockade were also not statistically different between the two groups during onset, maintenance, and regression of anesthesia, except that the light touch-to-pinprick and light touch-to-temperature zones of differential blockade were greater with bupivacaine than with tetracaine 30 min after subarachnoid injection. The width of the zones of differential blockade also remained unchanged within each group during onset, maintenance, and regression of anesthesia. Changes in, and absolute levels of, blood pressure and heart rate were similar with both bupivacaine and tetracaine throughout. We conclude that zones of differential sensory blockade are essentially the same with tetracaine and bupivacaine, that the widths of the zones of differential sensory blockade remain constant during onset, maintenance, and offset of spinal anesthesia, and that bupivacaine and tetracaine are associated with similar changes in heart rate and blood pressure during spinal anesthesia.

Adult↗
PubMedDate not supplied

Effect of isoflurane on endothelin-1 mediated airway smooth muscle contraction.

Endothelin-1 (ET-1) is an endogenously produced 21 amino acid peptide that can cause significant airway smooth muscle (ASM) constriction. Volatile anesthetics e.g. isoflurane, can attenuate ASM constriction. This investigation was undertaken to study the direct effects of isoflurane, at a clinically relevant dose, on endothelin-induced constriction in rat trachea. Five Sprague-Dawley female rats (weight 325-350 g) were euthanized. Four 2-3 mm rings were excised from the mid portion of the trachea, attached to a force transducer for isometric measurement, and were then suspended in jacketed baths containing 37 degreesC KH solution, bubbled with 95% O2 and 5% CO2. Carbachol dose-response curves (10(-8)-10(-4)M) were obtained to establish the maximal contractility (Cmax) for each tracheal ring. Carbachol was then washed out of the bath solution until the tissue tension returned to the baseline. Subsequently, ET-1 dose response curves (3-200 nM) were generated in the absence (ET-1, control) and in the presence of 2% isoflurane. Our data suggests that isoflurane at 2% concentration, attenuated ET-1 induced tracheal contraction at 100 and 200 nM concentrations by 20%. This is the first demonstration indicating that, at a clinically relevant dose, isoflurane depresses ET-1 induced ASM constriction.

Anesthetics, Inhalation↗
PubMedDate not supplied

Use of single-dose epidural morphine in a patient undergoing an abdominal aortic aneurysm resection.

To avoid possible trauma to the epidural venous plexus in a 56-year-old male who presented for abdominal aortic aneurysm resection, the authors preoperatively injected a single dose of epidural morphine rather than inserting an indwelling epidural catheter. The patient's intraoperative anesthetic requirements appeared to have been decreased, he was extubated shortly after the end of the procedure, and he experienced good postoperative analgesia. No untoward neurologic sequelae occurred. The authors feel that a single dose of epidural morphine, compared to epidural catheter placement when systemic heparinization is planned, decreases intraoperative anesthetic requirements, provides good postoperative analgesia, and may have the benefit of decreasing the possibility of epidural hematoma formation.

Anesthesia, Epidural↗
PubMedDate not supplied

Temporal correlation of succinylcholine-induced fasciculations to loss of twitch response at different stimulating frequencies.

STUDY OBJECTIVE: The present study was undertaken to determine the time courses of succinylcholine-induced fasciculations and adductor pollicis single-twitch responses at two stimulating frequencies. DESIGN: A prospective, randomized study. SETTING: The main operating room of a university teaching hospital. PATIENTS: Forty-four patients undergoing general anesthesia and requiring tracheal intubation. INTERVENTIONS: In 22 patients, anesthesia was induced with thiopental sodium, fentanyl, and midazolam and maintained with 70% nitrous oxide in oxygen prior to the administration of succinylcholine 1 mg/kg. In another 22 patients, end-tidal isoflurane 0.75% to 1% was included in the induction regimen. Patients in each group were randomly assigned to receive ulnar nerve stimulation at either 0.1 Hz or 1.0 Hz. MEASUREMENTS AND MAIN RESULTS: The times at which fasciculations were first noticed and no longer visible and the times to 25%, 50%, 75%, 90%, and 100% twitch depression were recorded. These times were compared for the two rates of neurostimulation. With single-twitch nerve stimulation at 1.0 Hz, 100% twitch depression occurred 6 +/- 16 seconds following the end of fasciculations, while at a stimulating frequency of 0.1 Hz, it occurred 52 +/- 32 seconds later (p less than 0.05). At the end of fasciculations, single-twitch depression of 50% or more was noted in only 19% of patients in the 0.1 Hz groups and in all patients in the 1.0 Hz groups (p less than 0.05). In the 0.1 Hz groups, 50% twitch depression occurred 19 +/- 27 seconds after the end of fasciculations, with more than three-quarters of the patients having achieved 50% twitch depression 30 seconds following the disappearance of fasciculations. The addition of isoflurane did not significantly alter any of these times. CONCLUSIONS: The data reveal that cessation of fasciculations may be an inaccurate clinical sign of the readiness for intubation and confirm that standardized methods of neurostimulation are necessary in the pharmacodynamic evaluation of neuromuscular blocking drugs. In settings where profound neuromuscular relaxation is not required, waiting at least 30 seconds beyond the disappearance of fasciculations should provide good intubating conditions.

Adolescent↗
PubMedDate not supplied

Variability of onset times within and among relaxant regimens.

STUDY OBJECTIVE: To evaluate the consistency of times to 95% twitch height depression (T95%) in groups of patients receiving identical induction and relaxant regimens. DESIGN: Prospective, noncontrolled, blinded study. SETTING: Ambulatory surgical unit at a university medical center. PATIENTS: Seventy-five ASA physical status I and II patients undergoing general endotracheal anesthesia. INTERVENTIONS: Patients received succinylcholine 1.5 mg/kg or a nondepolarizing regimen with doses ranging from approximately 1.5 to 6 times the ED95, with or without a priming dose. MEASUREMENTS AND MAIN RESULTS: For each of the eight relaxant regimens used in five or more patients, the intraregimen variability of T95% (at the adductor pollicis muscle upon ulnar stimulation at 0.1 Hz) was expressed as SD and range, and the individual data points were displayed. There was wide intraregimen variability. For each regimen, the slowest T95% was at least 73% longer than the fastest T95%. For the 16 patients receiving a priming dose plus an intubating dose 5 or more times the ED95, the median T95% was 95 seconds; however, T95% was beyond 120 seconds in 5 of the 16 cases. CONCLUSIONS: The wide variability in onset times among subjects receiving the same regimen indicates that monitoring of neuromuscular response, preferably to a relatively slow rate of neurostimulation, is essential if one elects to use moderate to high doses of atracurium and/or vecuronium for rapid-sequence induction in a patient in whom movement or coughing is unacceptable. Since onset times were not symmetrical about the mean, the magnitude and frequency of unacceptable onset times would not be fully appreciated unless the individual data points were displayed. Such information may be critical when reporting the suitability of a neuromuscular blocking drug for rapid intubation.

Adult↗
PubMedDate not supplied

The efficacy of intramuscular ketorolac in combination with intravenous PCA morphine for postoperative pain relief.

STUDY OBJECTIVE: To examine the efficacy of intramuscular (IM) ketorolac used in combination with intravenous (IV) patient-controlled analgesia (PCA) morphine for postoperative pain relief following intra-abdominal gynecologic surgery. DESIGN: Randomized, double-blind, placebo-controlled study. SETTING: Patient care unit at a university medical center. PATIENTS: Thirty-five healthy women undergoing intra-abdominal gynecologic surgery who requested postoperative PCA. INTERVENTIONS: Postoperatively, all patients received IV PCA morphine, with the PCA device programmed to deliver a maximum of 1 mg every 6 minutes (maximum of 30 mg over 4 hours). In addition, patients received one of three regimens: (1) IM saline every 6 hours; (2) IM ketorolac 30 mg while in the postanesthesia care unit (PACU), followed by 15 mg every 6 hours; or (3) IM ketorolac 60 mg while in the PACU, followed by 30 mg every 6 hours. MEASUREMENTS AND MAIN RESULTS: Patients were assessed at regular intervals. Visual analog scale (VAS) scores were used to assess analgesia and patient satisfaction with therapy. Data on morphine usage were obtained from the PCA device, and the frequency and severity of adverse effects were assessed for the presence or absence of side effects. Cumulative morphine dosages were lower (p less than 0.05) in both ketorolac groups at 12, 18, and 24 hours. VAS scores and the frequency of side effects did not differ significantly among groups. CONCLUSIONS: IM ketorolac significantly decreased PCA morphine requirements. The analgesic effects of the two drugs appear to be additive.

Adult↗
PubMedDate not supplied

Monitoring of neuromuscular function in the clinical setting.

This paper will review the basics of neurostimulation in the perioperative period. Following a brief overview of neuromuscular physiology, the mechanism of action of depolarizing and non-depolarizing relaxants will be discussed. The principles of neurostimulation will then be applied clinically when different patterns of stimulation (single twitch, train-of-four, post-tetanic twitch count, double burst) are described. Clinical assessment of neuromuscular function will then be compared with both subjective and objective means of assessment of adequacy of intraoperative relaxation and postoperative reversal. The principles reviewed in this paper will then be applied in the clinical setting, and risks and benefits associated with perioperative use of muscle relaxants will be discussed.

Humans↗
PubMedDate not supplied

Does tranexamic acid decrease bleeding in patients undergoing cardiopulmonary bypass?

We reviewed the records of 66 patients who underwent cardiopulmonary bypass; half of these patients received the plasmin inhibitor, tranexamic acid. The demographics were not different between the group who received tranexamic acid and the group who did not (control group). There was no difference in the heparin or protamine requirements between the two groups. There was a significantly greater amount of 12-hr chest tube bleeding in the control group (495 +/- 484 vs. 863 +/- 655 in the control and tranexamic acid groups, respectively; p < .02). There was no difference between the groups in either the post-operative hematocrit, platelet count or the number of patients requiring transfusion. Although tranexamic acid decreased the amount of chest tube output, there was no demonstrable patient benefit derived from its use.

Antifibrinolytic Agents↗
PubMedDate not supplied

Intravenous regional anesthesia with ketorolac-lidocaine for the management of sympathetically-mediated pain.

This retrospective study was undertaken to determine the usefulness of intravenous regional anesthetic (IVRA) blocks containing ketorolac and lidocaine in the management of sympathetically-mediated pain, and to determine what factors, if any, predicted success with this technique. Sixty-one patients with reflex sympathetic dystrophy presenting to a university-affiliated teaching hospital's pain management center were evaluated. Patients underwent one or more treatments with IVRA blocks containing ketorolac and lidocaine. The duration of pain, site of extremity affected, pain symptomatology, duration of relief from the first IVRA block, absence of pain following a series of IVRA blocks and side-effects from the IVRA blocks were determined. Of the 61 patients, 16 had complete response (26 percent), 26 had a partial response (43 percent) and 19 had no response (31 percent) to the ketorolac-containing IVRA. The only symptom which predicted a failure with this therapy was allodynia. No patient had serious side effects from the IVRA block; dizziness following tourniquet release occurred in 41 percent (n = 25) of the patients. IVRA block containing ketorolac is a useful and minimally invasive technique for the management of patients with reflex sympathetic dystrophy.

Adult↗